Throughout the specification and claims, the term "separation" means the removal of pollutants from a fluid flow by velocity or direction change of the fluid flow or by centrifugal action, while "filtration" means the removal of pollutants from a fluid low by the fluid passing through a porous medium to remove the pollutants by a filtering action.
Various filtering units are known for filtering pollutants from a flow of air, these including horizontally rotating self cleaning cylindrical filter elements, vertically positioned cylindrical units with vibrational self cleaning, corrugated vertically positioned self cleaning filter units with the air flow being radially inwardly of the filter, cylindrical filters with radially outward flow, horizontally mounted cartridge filters with air cleaning, vertical cartridge filters with pulse jet cleaning by temporarily reversing the flow of air, and conical vertically orientated pleated filter elements.
Also there are various units with an independent inertial separator such as a cyclone connected by duct or connection to an independent chamber containing a filter.
Also U.S. Pat. No. 5,240,486 discloses a condensate separator for separating liquids from gases in which the gas flows into a first element end exits via a transverse port into a separator cavity where the liquid, that is formed by condensation due to the change of gas flow direction is collected. The first element has a funnel shaped end which assists in changing the gas flow direction, the funnel being placed immediately in front of the entry into the second element.
Also JP 60005216 shows a dust collector having an intake pipe vertically introduced into a cylinder having a funnel-shaped lower portion and has its lower end opened into the cylinder. The discharge pipe is positioned in the cylinder above the lower end of the funnel, which is designed in an inverted frustoconical form.
Attention is also directed to RU 2,057,574 which illustrates an example of inertia separation of particles from a fluid stream.
However as far as is known none of the prior art filtering or particle separation machines have inertial separation as an integral part of a cartridge filter housing.
Thus it is an object of the invention to provide a filter or separation unit which will overcome one or more of the disadvantages of the prior art.
Another object of the invention is to provide a filter cartridge of generally cuboid shape including inertial separation and filtering of the fluid flow.
A further object of the invention is to provide a cartridge housing which houses filter elements wherein the housing has an inertial separator which is an integral part of that housing and which is positioned between the filter elements.
Also it is an object of the present invention to provide a filtering unit in which there is separation of the larger particles by inertia and change of direction of the flow before the flow passes through the filter elements.
A further object of the invention is to provide the filtering elements as pleated elements which are cleaned from the clean side of the filter element by either vibration and/or air jet blast.
A still further object of the invention is to provide means where during operation of the unit the lower portion of the filter elements are closed, at other times are not closed to allow for the free fall of the filtered material to pass into a collection area.
Another object of the invention is to provide a separation and filtering unit in which there are two stages of inertial separation prior to two stages of filtration of a fluid flowing through the unit.